2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1990, 1993
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35 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93";
37 #endif /* LIBC_SCCS and not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
41 #include <sys/types.h>
43 typedef intptr_t word; /* "word" used for optimal copy speed */
45 #define wsize sizeof(word)
46 #define wmask (wsize - 1)
49 * Copy a block of memory, handling overlap.
50 * This is the routine that actually implements
51 * (the portable versions of) bcopy, memcpy, and memmove.
53 #if defined(MEMCOPY) || defined(MEMMOVE)
62 (void *dst0, const void *src0, size_t length)
67 bcopy(const void *src0, void *dst0, size_t length)
71 const char *src = src0;
74 if (length == 0 || dst == src) /* nothing to do */
78 * Macros: loop-t-times; and loop-t-times, t>0
80 #define TLOOP(s) if (t) TLOOP1(s)
81 #define TLOOP1(s) do { s; } while (--t)
83 if ((unsigned long)dst < (unsigned long)src) {
87 t = (uintptr_t)src; /* only need low bits */
88 if ((t | (uintptr_t)dst) & wmask) {
90 * Try to align operands. This cannot be done
91 * unless the low bits match.
93 if ((t ^ (uintptr_t)dst) & wmask || length < wsize)
96 t = wsize - (t & wmask);
98 TLOOP1(*dst++ = *src++);
101 * Copy whole words, then mop up any trailing bytes.
104 TLOOP(*(word *)(void *)dst = *(const word *)(const void *)src;
105 src += wsize; dst += wsize);
107 TLOOP(*dst++ = *src++);
110 * Copy backwards. Otherwise essentially the same.
111 * Alignment works as before, except that it takes
112 * (t&wmask) bytes to align, not wsize-(t&wmask).
117 if ((t | (uintptr_t)dst) & wmask) {
118 if ((t ^ (uintptr_t)dst) & wmask || length <= wsize)
123 TLOOP1(*--dst = *--src);
126 TLOOP(src -= wsize; dst -= wsize;
127 *(word *)(void *)dst = *(const word *)(const void *)src);
129 TLOOP(*--dst = *--src);
132 #if defined(MEMCOPY) || defined(MEMMOVE)